1. Field of the Invention
This invention relates to a liquid discharge head for discharging liquid and effecting recording by flying liquid droplets. More particularly, the invention relates to a liquid discharge head applicable to an apparatus such as a facsimile apparatus having a printer, a copier and a communication system for effecting recording on a recording medium such as paper, thread, fiber, cloth, leather, metals, plastics, glass, wood or ceramics, and a word processor having a printer portion, and further an industrial recording apparatus compositely combined with various processing apparatuses, and a method of manufacturing the liquid discharging head.
xe2x80x9cRecordingxe2x80x9d in the present invention means not only imparting images such as characters and figures having meanings to a recording medium, but also imparting images such as patterns having no meaning to the recording medium.
2. Related Background Art
An ink jet recording apparatus for discharging recording liquid (ink) from the discharge port (orifice) of a liquid discharge head to thereby effect recording is known as a recording apparatus excellent in such points is low noise and high-speed recording. As such ink jet recording apparatuses, ones of various types have heretofore been proposed and improved, and some of them have already been commercialized or are being developed for practical use.
An example of the ink jet recording apparatus according to the prior art, as shown in FIGS. 14 and 15 of the accompanying drawings, has a liquid discharge head comprised of an orifice plate 200 for discharging ink, a top plate 210 for forming a flow path 202 communicating with a discharge port 201, and a substrate 204 having an energy generation element 203 provided in the flow path 202 and generating energy for discharging liquid.
The minute discharge port 201 for liquid discharge provided in the orifice plate 200 is an important element which governs the discharging performance of the liquid discharge head. That is, the orifice plate 200 of the liquid discharge head is required to be formed of a material having good workability for forming the minute discharge port 201 and having a good ink-resisting property for the direct contact with the ink. Heretofore, as a material satisfying such conditions, use has been made of a metal plate of stainless steel, nickel, chromium, aluminum or the like, or resin film easy to obtain a desired thickness and inexpensive, such as polyimide, polysulfone, polyether sulfone, polyphenylene oxide, polyphenylene sulfide or polypropylene.
Japanese Patent Application Laid-Open No. 2-204048 discloses a liquid discharge head of a construction in which a portion of an orifice plate enters into a flow path to improve discharge efficiency. Specifically, this liquid discharge head is of a construction in which a part of the material forming the orifice plate is softened by heat and comes into the flow path, and thereafter forms a discharge port. Further, U.S. Pat. No. 5,604,521 discloses a liquid discharge head which uses an orifice plate having a convex portion formed with an orifice and provided on a joined surface with the main body of the head and in which adhesive resin is applied to the joined surface of the orifice plate, whereafter the convex portion is fitted into a flow path.
However, when the liquid discharge head has the convex portion to be fitted into the orifice, the discharge port assumes a tapered shape and therefore, when the flow path is to be highly densely arranged, the highly dense arrangement of the convex portion has been limited.
It is an object of the present invention to provide a liquid discharge head having:
an orifice plate in which a plurality of discharge ports for discharging liquid droplets therethrough are arranged in a row; and
a head body provided with a plurality of flow paths communicating with the plurality of discharge ports, a liquid chamber for supplying liquid to the plurality of flow paths, and a plurality of energy generation elements disposed correspondingly to the plurality of flow paths and generating energy for discharging the liquid droplets;
the orifice plate being joined to the joined surface of the head body in which the communication ports of the flow paths communicating with the discharge ports are disposed;
characterized in that the orifice plate is formed with wall-shaped convex portions protruding from the inner peripheral portions of the discharge ports and having at least a portion thereof entering from the communication ports into the flow paths, and
the width of the wall-shaped convex portions is greater in the portions thereof parallel to the row direction in which the plurality of discharge ports are arranged than in the portions thereof orthogonal to the row direction.
It is another object of the present invention to provide a liquid discharge head having:
an orifice plate in which a plurality of discharge ports for discharging liquid droplets therethrough are arranged in a row; and
a head body provided with a plurality of flow paths communicating with the plurality of discharge ports, a liquid chamber for supplying liquid to the plurality of flow paths, and a plurality of energy generation elements disposed correspondingly to the plurality of flow paths and generating energy for discharging the liquid droplets;
the orifice plate being joined to the joined surface of the head body in which the communication ports of the flow paths communicating with the discharge ports are disposed;
characterized in that the orifice plate is formed with wall-shaped convex portions protruding from the inner peripheral portions of the discharge ports and having at least a portion thereof entering from the communication ports into the flow paths, and
on the joined surface side of the orifice plate to the head body, as compared with the inner end portions of the discharge ports at positions orthogonal to the row direction in which the plurality of discharge ports are arranged, the wall-shaped convex portions located in parallelism to the row direction are formed high in the direction of thickness of the orifice plate.
It is still another object of the present invention to provide a method of manufacturing a liquid discharge head having:
an orifice plate in which a plurality of discharge ports for discharging liquid droplets therethrough are arranged in a row; and
a head body provided with a plurality of flow paths communicating with the plurality of discharge ports, a liquid chamber for supplying liquid to the plurality of flow paths, and a plurality of energy generation elements disposed correspondingly to the plurality of flow paths and generating energy for discharging the liquid droplets;
the orifice plate being joined to the joined surface of the head body in which the communication ports-of the flow paths communicating with the discharge ports are disposed;
characterized in that the orifice plate is formed with wall-shaped convex portions protruding from the inner peripheral portions of the discharge ports and having at least a portion thereof entering from the communication ports into the flow paths, and
the wall-shaped convex portions are formed by laser working after the discharge ports have been formed by laser working.
Other objects and features of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawings.